1. Field of the Invention
The present invention relates to a system and method for identifying biological samples.
2. Background Art
Identification of biological samples is of critical importance. For example, tests on a particular patient's blood sample may reveal an illness requiring medical treatment. If the sample cannot at all times be identified and associated with the patient from whom the sample was taken, the patient may be denied necessary treatment, or undergo unnecessary treatment.
Biological samples, including blood samples, are often placed in individual containers such as test tubes or vials. A common method of identifying a sample is to provide sample identifying information on the container. In one arrangement, identification data such as a patient's name, social security number or other identification number is printed or written on a label that is placed on the container in human readable form. In other arrangements a printed bar code label is affixed to each container.
One problem with these identification arrangements or schemes is that they are not universal, but specific only to the organization which develops and implements the arrangement or scheme. A hospital may use one identification scheme and an outside laboratory may use another completely incompatible scheme. As a result, even though the scheme may properly identify the sample when it is at the hospital, it may provide no usable identification when the sample is sent to the outside laboratory.
Another problem with these prior art schemes is that they do not ensure unique identification of each container. For example, if a patient's social security number is used as the identifier, all samples for that patient will use the same identifier. As a result, the identification system may not facilitate the unique identification of the later samples when a sample is split or additional samples are obtained from that patient.
These prior art identifying arrangements and schemes also permit tampering. For example, a patient may provide the wrong social security number or name, resulting in duplicity with other samples belonging to a patient having that true number or name.
For a scheme that marks the container with human readable information, another problem is the lack of patient confidentiality. Anyone who encounters the sample may easily identify the patient to which the sample corresponds.
The use of these types of identification systems also requires an organization to implement a particular system, including obtaining the necessary marking and detection equipment. For example, if a hospital chooses to bar code label its sample containers, appropriate label printing and reading equipment must be obtained.
Numerous problems are associated with identification systems that require the user to place a label on each container. The label may be misprinted, may be affixed to the wrong container, may become damaged and unreadable, or may become separated from the container. Labels also present problems to automated label detection apparatus or equipment. When the container is used by more than one organization, multiple labels may be placed over one another on a single container, changing the dimensions of the container. The change in dimension of the container may prevent the container from being used with certain equipment or may damage the equipment.
Normally each label is affixed with adhesive to the container. When the container has a curved outer surface, the ends of the label tend to pull away from the container surface. When the container is subsequently moved through automated detection equipment, loose portions of the label may be damaged or may damage the detection equipment. Adhesive may also be transferred from the label or container to the detection equipment, damaging the equipment.
Another problem with labels is that they are very often opaque. For example, to easily permit a user to read written information, labels are often white paper written on with dark ink. As a result, the label obscure the view of the contents of the container. This is very disadvantageous when, for example, it is necessary to view the level of a fluid in the container. Even if the label is fairly transparent, the printed areas of the label are likely to be opaque.
For automated equipment to be able to read these labels, the labels must often be specifically oriented on the container and the container must be specifically oriented with respect to a detection apparatus of the equipment. This may require that an operator align the label on each container with the detection apparatus.
Another problem with prior art identification schemes is that they often do not provide sufficient data space for all of the desired information. Only a small amount of information may be written or printed on a blank label.
There are other problems which specifically relate to the use of bar code labeling systems. A first problem is that the contents of the container may interfere with the detection of the bar code information. The bar code comprises printed dark bands on a light substrate. Detection of the bar code is accomplished by sensing the intensity of diffuse light reflected from the bar code area. If the contents of the container are dark, the differences in light intensity between the printed bar code bands and surrounding substrate may be difficult to ascertain, interfering with the bar code detection.
A system and method for identifying biological samples that overcomes the above-stated problems is desired.